Dash: dash: heap out-of-bounds write in conv_escape via undersized unicode escape reservation
Summary
| CVE | CVE-2026-102474 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-29 10:17:10 UTC |
| Updated | 2026-09-29 21:29:07 UTC |
| Description | A flaw was found in dash. The printf builtin reserves four bytes before converting a Unicode \u or \U escape, but the multi-byte token can need five or six bytes. A local user who can supply such an escape to dash printf or echo %b, including through dash -c and a positional argument, can write one or two bytes past that reservation. |
Risk And Classification
Primary CVSS: v3.1 4 MEDIUM from [email protected]
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.001440000 probability, percentile 0.030640000 (date 2026-09-29)
Problem Types: CWE-787 | CWE-787 Out-of-bounds Write
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 4 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 4 | MEDIUM | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-102474 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-29T08:31:49.562Z | Reported to Red Hat. |
| CNA | 2026-09-29T00:00:00.000Z | Made public. |
Workarounds
CNA: No practical runtime mitigation is available in the shipped build. Do not pass untrusted data into dash printf/echo %b or into dash -c as a positional argument. The fix is to raise the CHECKSTRSPACE reservation at both printf call sites to 8. The later unaligned-access memcpy change in conv_escape does not enlarge that reservation and does not fix this issue.
There are currently no legacy QID mappings associated with this CVE.